The Sunfire amplifier is much lighter than most amplifiers, much less than one expects from an amplifier capable of this level of power output. One thing youll notice right away that makes the Sunfire different, is the lack of ventilation on the top of the chassis. There are some small slots on the side, but the amplifier runs super coola huge plus for locating the amplifier in an enclosed cabinet. The unit I was sent is the called the Architects Choice. This means that the unit is 17 wide as opposed to the normal 19 version and boasts better noise specifications in comparison to the original Sunfire Cinema Grand Signature. There is a newer series II version that has slightly more power (~20 W), and has comparable specs otherwise. Apparently, there were requests from installers who need smaller widths in order to use special cabinetry like that from Middle Atlantic.

I set the amplifier to the always on position after verifying the signal sensing worked properly. The unit has a 30-minute delay before turning off when no signal is present, and its turn on is almost instantaneous. If you want to conserve electricity, then this would be the proper setting (the switch is small and on the back, so turning it on manually would be a hassle otherwise). I let the amp cook for a period of weeks with both music and film before any critical listening.

The manual suggests a few different ways to experiment with the current and voltage source outputs. The voltage source outputs are designed to have an impedance of zero ohms. This will help to ensure accurate frequency response with different loudspeaker systems. The current source outputs have a source impedance of one ohm. This simulates the resulting output you might get when utilizing certain tube amplifiers. These outputs are available for the front three (L/C/R) channels. It is your choice whether to use these outputs or not. It is possible to use them separately or in combination, i.e. the voltage outputs for the bass, and the current outputs for the treble in a system that is capable of bi-wiring.

The Cinema Grand Signature makes biamplification easy. All that is necessary (assuming you dont have dual preamplifier outputs) is to connect two of the outputs together with an RCA cable. There are dual RCA inputs, so one jack can be used to connect to another set of inputs. This allows using two channels of the amplifier for one speaker. Then you can choose whether to use current and voltage outputs, or both voltage outputs.

I didnt happen to have bi-wire cables at the time of the review; so all comments are single wire. (Later I found outdue to level differencesthat this may have been an unfair test anyway.) The sound from current/voltage source bi-wiring will be different depending on each speaker that is used, so it is recommended you try all the combinations available to you in your own system.

The manual has diagrams and easy-to-read sections that will help with connection and proper use of the amplifier. I should mention that the Sunfire components come with a base that consists of a piece of glass with rubber feet. This provides a good shelf if the amplifier is put on the floor or on carpetwhere blocking the ventilation underneath would be an issue.

The AC cord is detachable, but is of the 2-prong variety.

Listening Tests

I used the balanced inputs on the Signature amplifier for all the listening tests in System 1. At first I thought Id listen to the current output vs. the voltage output to get a feel for the different flavor of sound offered. I used track 4, Voodoo Woman, from Lonnie Liston Smith and The Cosmic Echoes album Expansions. I tended to prefer the sound of the voltage outputs after going back and forth a few times. High frequencies seemed to stand out more (in a good way), and bass guitar seemed bigger. With the current outputs the highs were more reticent, and it almost sounded as if the level was reduced in comparison.

To check my findings I tried track 6, Gypsy, from disc 2 of Fleetwood Mac  25 Years The Chain box set. With the voltage, I could hear Stevie Nicks clearly licking her lips, and the highs were sparkly but not sizzly. There was good dynamic presence and there seemed to be more detail in comparison with the current outputs. With the current outputs the whole presentation seemed softer. The differences were extremely subtle, and youd have to try the differences in your system to check which would be preferable. I still had a nagging sense that the overall level was reduced, so I checked with a multimeter. Sure enough, there was a slight drop in level from the current outputs that would most definitely account for some of the relaxed treble and softening of the sound I heard. It might have also accounted for some of the difference in presence and impact. Im convinced that some of the differences still existed regardless of level changes, but you should keep this in mind if you plan to bi-wire or do comparisons with other systems.

From this point on, all the listening tests were done with the voltage outputs. For 2-channel comparisons I used my trusty not-so-old Krell KST-100 amplifier. I began with track 2, Words Get In The Way, from Gloria Estefans Greatest Hits record. The Sunfire had a slight relaxed quality to the sound. Bass seemed punchier and voice was more expansive. The Krell sounded more etchedwith more ka-chunk to the sound. Voice is more present, but not as smooth as with the Sunfire amplifier. I would say there was more upper high frequency content, but this did not give an advantage one way or the other.

Next, I put track 5, Seamus, from the Mobile Fidelity recording of Pink Floyds Meddle. The Sunfire exhibited easiness to the sound that was particularly seductive. Tonally the sound was very fine with the howling of the dog clearly set apart from the voice, guitars, and other instruments. The Krell produced a tad more air around the images that gave just a slight amount of clarity or sharpness to the music. This could easily turn to edginess if the recording leaned toward hardness. This quality made the dog stand out even more than with the Sunfire, but the voice was not as smooth. It would be hard to determine if there was more resolution or if the amplifier was bringing out the sibilance and other artifacts on the record. The choice of speaker and ancillary electronics would play a big part in matching, as often is the case.

To see what the sound would be like with a little classical, I put on the Allegro (track 1) from the Telarc recording (CD-80108) of Mozarts Eine Kleine Nachtmusik, K. 525. The Sunfire slowed things downthe pace of the passages seemed slower. Impact was not as in-your-face as with the Krell. The amplifier never exhibited a lack of control. The Krell had more apparent depth to the soundstage. The Sunfire presentation was farther back entirely. Extra high frequency content as presented by the Krell suggested more detail and delicacy, and micro-dynamics were always good. The Sunfire is more laid back in general and not as incisive sounding, though very pleasant to listen to.

For more casual listening, I put on track 8, You Are Not Alone, from Michael Jacksons HIStory album. At really high volumes the Sunfire skated along with no signs of stress. I dont think I would ever worry about running out of power; the big concern would be damage to your ears due to playback level!

To end the 2-channel testing I put on track 6, Earl Klugh on Blue N Soul (a sampler), doing I Heard It Through The Grapevine. Guitar sound was silky smooth and notes seemed to flow out of the speakers. There was lots of air on the recording, and the Sunfire did a fantastic job presenting the acoustic space. Bells and percussive sounds complemented the other instrumentation nicely.

I used System 1 for casual video use during the review period, but hooked up the Sunfire to System 2 for more serious surround listening. In addition to a few of the DVD-A discs I reviewed, I listening to several clips from different DVD movies. Those discs include: chapters 6 and 16 from The Fifth Element, chapter 2 from Gladiator, chapters 1 and 10 from Charlies Angels, and chapter 15 from U-571. The Sunfire had superb dynamic capability, and excellent clarity regardless of level. It was easily able to drive this speaker system, and did it well. It would make an excellent choice in just about any surround system.

Conclusion

It is usually a bad sign when you really cant think of much to say about an audio component, but in this case it signifies quite the opposite. The Sunfire did exactly what you hope of any piece of equipment, but rarely happens: it worked just as it should. The Sunfire Signature amplifier offered tremendous power, ability to drive any load easily, virtually heat-free operation, two types of outputs to match to various tastes in sound, and aside from a slight tendency towards mellowness, an extremely neutral lack of soundhigh praise for a high quality amplifier.